Summer 2024

Understanding Defensible Space Zone 0

by Hedwig Van Den Broeck

As we continue our series on "Home Landscaping for Fire Safety", we will now delve deeper into the topic of developing fire-resistant landscaping in Fire Zone 0.

Zone ZERO means Zero combustibles
Defensible Space Zone 0 refers to the immediate area (0–5 ft.) surrounding your home, which includes decks and other structures. This area needs to be carefully managed to reduce the likelihood of fire ignition and spread by removing all receptive fuel beds.

While traditional landscaping often includes fire-resistant plants, it is vital to consider landscaping strategies that minimize plant materials altogether, focusing instead on the use of non-combustible materials.

Embracing these strategies ensures that your landscape not only enhances the beauty of your property but also serves as a proactive defense against wildfire risks.

What are Embers?

Ahead of a wildfire, the wind can carry small burning particles known as embers, also called firebrands. Homes can burn down due to embers, radiant heat, or direct flame. Embers are responsible for most building ignitions. They can lodge themselves inside your foundation plants, under doors and windows, in cracks and crevices, in accumulated debris, etc. 

Your home is ‘Ground Zero’ and the objective of Zone 0 is to keep embers from damaging your home while also enabling firefighters to navigate safely in the event of a wildfire.
Watch this simulation of a home ignited by embers to see just how dangerous wind-blown embers can be.

Prepare Your Home - Courtesy UCANR

Hardening your home
You can take important steps to ensure that your home can resist ember ignition by installing non-flammable siding, removing combustible materials next to your home, sealing any opening into the home, enclosing soffits, installing tempered glass double pane windows, correctly installing gutters and gutter guards, and installing ember proof fire vents (or you can install wildfire defense mesh over existing vents)

In the immediate area (0–5 ft.) around your home, create a non-flammable ‘apron’ clear of anything that can burn. Consider hardscape materials, such as cement, pavers, rock, and gravel. Remove all flammable hazards that are within this critical zone: such as flammable mulch, firewood, construction materials, propane tanks, flammable furniture/cushions, and all vegetation. Prune nearby tree canopies to preserve 10-foot clearance from the roof edge and keep this area free of windblown debris. Replace wood fencing and gates within this zone with metal, non-flammable cement block, or similar material.

Fire Resistant property - Courtesy Pexels-Max-Vakbovycnht

We cannot control the weather; we can, however, control the fuel!
Designing your landscape with Defensible Space Zone 0 in mind is not just about complying with regulations—it’s about safeguarding your home, family, and community from the devastating effects of wildfires.
Following the principles of defensible space might seem overwhelming at first, but even small actions you take can make a big difference. And if you really must have that beautiful potted plant, welcoming your friends and family, at your front door, go ahead, just make sure you plant fire-resistant plants in a non-flammable container well surrounded by non-flammable hardscaping.

Our series on 'Home Landscaping for Fire Safety' will continue with Defensible Space Zone 2, 'the Lean, Clean, and Green Zone', which will be published in the fall issue of News to Grow By.

References:
For more information on covering your vents, UCANR has a detailed guide.
UCANR Wildfire Preparation site offers specific guidance and ideas.
For more tips on how to protect your home, CAL FIRE offers a Low-Cost Retrofit List.
IBHS – Wildfire Prepared: Home Preparedness Guide.
MOFD Abatement Requirements
Firesafe Marin:
Plan Your Fire-Smart Landscape
Hardening your Home 
Video zone 0
Insurance Institute for Business and home safety https://ibhs.org/wildfire/wildfire-demo-2019/